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From: Dave Chinner <david@fromorbit.com>
To: Eli Morris <ermorris@ucsc.edu>
Cc: xfs@oss.sgi.com
Subject: Re: xfs_repair of critical volume
Date: Wed, 17 Nov 2010 18:47:08 +1100	[thread overview]
Message-ID: <20101117074708.GP22876@dastard> (raw)
In-Reply-To: <A219F774-E2D5-4CEB-AB2B-399F3053DFF9@ucsc.edu>

On Tue, Nov 16, 2010 at 11:29:41PM -0800, Eli Morris wrote:
> Hi Dave,
> 
> Thanks a lot for your help. I looked at the man page and elsewhere for this info and can't find what this means:
> 
> 
> extent: [startoffset..endoffset]: startblock..endblock
> 
> 
> I understand what an offset would be, but what the heck is a startoffset and an endoffset? 

startoffset: file offset of the start of the extent
endoffset: file offset of the end of the extent

> Is the formula for the location of the file:
> 
>  startoffset + startblock through endoffset + endblock, where the blocks and the offsets are in 512 bytes?

no.

> So this file:
> 
> 0: [0..1053271]: 5200578944..5201632215
> 
> would be contained from:
> 
> beginning: 	(0 + 5200578944) * 512 bytes
> ending:		(1053271 + 5201632215) * 512 bytes

No, it translates like this:

    Logical		  Physical
File Offset (bytes)	block on disk
-------------------     -------------
   0 (0..511)		5200578944
   1 (512..1023)	5200578945
   2 (1024..1536)	5200578946
 .....			.....
1053270			5201632214
1053271			5201632215

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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  reply	other threads:[~2010-11-17  7:45 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-31  7:54 xfs_repair of critical volume Eli Morris
2010-10-31  9:54 ` Stan Hoeppner
2010-11-12  8:48   ` Eli Morris
2010-11-12 13:22     ` Michael Monnerie
2010-11-12 22:14       ` Stan Hoeppner
2010-11-13  8:19         ` Emmanuel Florac
2010-11-13  9:28           ` Stan Hoeppner
2010-11-13 15:35             ` Michael Monnerie
2010-11-14  3:31               ` Stan Hoeppner
2010-12-04 10:30         ` Martin Steigerwald
2010-12-05  4:49           ` Stan Hoeppner
2010-12-05  9:44             ` Roger Willcocks
2010-11-12 23:01       ` Eli Morris
2010-11-13 15:25         ` Michael Monnerie
2010-11-14 11:05         ` Dave Chinner
2010-11-15  4:09           ` Eli Morris
2010-11-16  0:04             ` Dave Chinner
2010-11-17  7:29               ` Eli Morris
2010-11-17  7:47                 ` Dave Chinner [this message]
2010-11-30  7:22                   ` Eli Morris
2010-12-02 11:33                     ` Michael Monnerie
2010-12-03  0:58                       ` Stan Hoeppner
2010-12-04  0:43                       ` Eli Morris
2010-10-31 14:10 ` Emmanuel Florac
2010-10-31 14:41   ` Steve Costaras
2010-10-31 16:52 ` Roger Willcocks
2010-11-01 22:21 ` Eric Sandeen
2010-11-01 23:32   ` Eli Morris
2010-11-02  0:14     ` Eric Sandeen
  -- strict thread matches above, loose matches on Subject: below --
2010-10-31 19:56 Eli Morris
2010-10-31 20:40 ` Emmanuel Florac
2010-11-01  3:40   ` Eli Morris
2010-11-01 10:07     ` Emmanuel Florac
2010-10-31 21:10 ` Steve Costaras
2010-11-01 15:03 ` Stan Hoeppner

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